1. Field of Invention
The invention relates to a card holder with the electric supplying function.
2. Related Art
Recently, the radio frequency identification (RFID) technology is gradually developed. The RFID system has the non-contact property, wide-directional property, long lifetime and strong weather-resistant property, so the application fields thereof are getting wider and wider. For example, the RFID system may be applied to an identification card for entrance security control, a stored-value card for a metro system, or tickets for various games.
The RFID system may be divided into a reader and a tag. The tag may be applied in the form of a card, and does not have any electric power stored. Thus, the tag is induced by an electromagnetic wave signal, which is outputted by the reader, to generate the electric power and thus transfer the stored information back to the reader. Then, the reader generates the identification function. The RFID system serving as the identification card or the stored-value card mainly utilizes the low frequency band. Thus, the effective distance from the card to the reader is shorter (usually shorter than 1 meter). That is, the card cannot work with the reader if they are too far away from each other or the card is not located within the transmission range of the electromagnetic wave signal of the reader, and the function of the card is thus limited.
In addition, if the RFID system is applied to the stored-value card, the card serving as the RFID tag does not have the displaying function. If the residual value of the card has to be inspected, the reader has to be provided to read the card and display the residual value of the card. Thus, the convenience in use is deteriorated, and the user may have risks in using the card because he or she does not know the residual value of the card.
Therefore, it is an important subject to design an additional part to enhance the convenience of using the RFID card.